hubFS: THE place for F#

Is it at all possible or ever be possible to define functions in terms of each other. A simple example is

let func1 xs = map func2 xs
let func2 ys = map func1 ys

I know this is something you wouldn't generally do but something you would probably want to do is

type 'a Tree = Nd of 'a * 'a Tree List
type 'a Forest = 'a Tree List
//fold trees
let foldt f g (Nd(a,ts)) = f a (foldf f g ts)
//fold forests
let foldf f g ts =  g (map (foldt f g) ts)

Sure, you want to use let rec ... and ....

let rec func1 xs = map func2 xs
and func2 ys = map func1 ys

N.B. This code will have a type error but that's a different issue.